Помогииите!!! Вставить подходящие слова из скобок)!!!!!

Look at this building. It is the city's (older; elder; eldest; oldest) building. It (opens; opened; was opening; has opened) in 1635. Today this building is even (greater; great; more great; greatest). Make sure you (regret; have regret; don't regret; will regret) if you spend more time to enjoy it. Many visitors enjoys (to watch; watch; watching; watches) its beauty.​